Jay, I can't shoot tight groups with open sights from the bench anymore because the sights are too close to my eyes. (old age ya know.) That is why I shoot creedmore like we did in silhouette. It puts the gun farther away. It is very hard to group this way every day because some days I hold real steady and others not so steady. Must depend on how much ridge ripple I had the night before! The whole thing with open sights is how good you can see them. If you are getting at least 3 in an inch, you are OK. Don't worry about it that much. I know you can control the trigger pull and don't flinch so just enjoy the shooting.
I am done experimenting with loads because I know what works. I have been trying to pass this along so everyone can try it themselves. I get a LOT of resistance about magnum primers. The force of some magnum primers can actually drive the bullet into the forcing cone before the powder starts to burn good. This has the effect of shooting different length brass with different internal capacity. It can also raise pressures when the boolit stops at the forcing cone and the pressure reaches it, sort of like a bore restriction. This is even more important when case tension on the boolit is weak. The crimp, no matter how strong will NOT prevent this. You can't correct for tension with a crimp. I spent years experimenting with everything from no crimp to a full profile crimp strong enough to ruin brass. All the crimp you want is just enough to prevent boolits from moving under recoil, no less, no more. A very heavy boolit does help the powder burn. The lighter a boolit is the quicker it can be blown out. I am a firm believer in mild primers for revolvers and also BPCR's. Testing since 1956 has taught me something I hope.
I do not see the same problem with small pistol magnum primers in the .357. I get good results with them there.
When I was young and shooting silhouette, I could focus on the sights AND the target. Both were clear. Those days are gone now. All you have to remember is you can only shoot as good as you can see. Unless you are Bob Munden, darn guy doesn't even have to look at his gun. I think he burns 3,000 or more rounds a week and it cound be much more then that. If you look at his hands when he shoots on American Shooter, they are black from powder.

Jay, something of interest. I used 4227 in my Blackhawk .357 super mag. It did NOT give me the problems I had in the .44. In fact when I took the new gun to a shoot, I shot 39 out of 40 WITH NO SIGHT SETTINGS. I only took it to get sight settings and to see what it would do. I should have kept that gun! All the top shooters were winning with the Dan Wesson so I traded for one. What a piece of junk! Three trips to the factory and it went fast at a gun show, good riddance. You had to buy 10 of them and pick the best and sell the rest. My barrel was not in the frame straight, the cylinder was not faced square, end shake was horrible, trigger pull must have been 10# and the cylinder lock wobbled.